package com.example.testdemo.testdemo.concurrent;

import java.util.concurrent.TimeUnit;

/**
 * @author Woo_home
 * @create by 2019/10/21
 */
public class ThreadLocalDemo {

    //第一次get()方法调用时会进行初始化（如果set方法没有调用），每个线程会调用一次
    private static final ThreadLocal<Long> TIME_THREADLOCAL = new ThreadLocal<Long>(){

        protected Long initialValue(){
            return System.currentTimeMillis();
        }
    };

    public static final void begin(){
        TIME_THREADLOCAL.set(System.currentTimeMillis());
    }

    public static final long end(){
        return System.currentTimeMillis() - TIME_THREADLOCAL.get();
    }

    public static void main(String[] args) throws Exception{
        ThreadLocalDemo.begin();
        TimeUnit.SECONDS.sleep(1);
        System.out.println("Cost: " + ThreadLocalDemo.end() + " mills");
    }
}
